Since my 55 Chevy project (affectionately named "Blue Jean"!) is in need of a complete re-wiring job, I thought I'd document the process as I go along to show everyone just how easy it is to wire a car from scratch, giving it the bare essentials needed to start, run and drive in a reliable and semi-neat looking fashion! SO many folks are intimidated about the notion of wiring a car from scratch, but if I can do it, then any oaf can...so hopefully once this series is done, then you'll see just how simple it can really be! That isn't to say that it's something you'll breeze through in an hour...it's time-consuming and, at times, tedious...but it is NOT difficult in the least! Start out by planning just what you want your car to have in the way of electrical systems and components. You'll need to know everything that will be included, and where each component will ultimately be located so that you can gain a general idea of how much wire you'll need, which connectors and terminals will be required, and how you may want to route your harness. In this case, my car will have just the basics, plus a few options left open for 'on down the road'. I want it to have brake lights, tail lights, headlights, front marker (parking) lights, wipers, a heater, radio, dash lights, a few gauges, and of course the wiring needed to start and run the engine as well as a functional charging circuit. I opted to skip turn signals because I hardly use 'em anyhow...and I think it's cool to use hand signals (and occasional hand gestures!) when driving an old heap! There also won't be any air conditioning, power windows or locks or any of that fluff going on here! Like I said...just the basics...a no-frill electrical system that ANYONE can wire from the ground-up, as I hope to demonstrate in the coming weeks (you know, as time, weather and funding permit!). Once you know what components you want your ride to have, you can form a mental 'game plan' and begin gathering up your basic supplies. At the very LEAST you're going to want to have lots of wire in the color(s) of your choice, a large selection of solderless "crimp connectors", assorted terminal ends, LOTS of quality electrical tape (believe me...get several rolls of quality tape!), a good pair of wire cutters, a good pair of stripper/crimpers, new bulbs, switches and sockets as needed, and two six-fuse mini-panels from Buss (not to mention the fuses to go into them!). That's an icomplete list...stuff will come up as you go, but it gives you a 'heads up' as to what you'll want to have on hand. Now, to start the project! I tend to start at the ends and work my way to the middle. That is to say, I do the rear lights and what I call the 'rear light harness', followed by the front lights and the 'front light harness', then the engine wiring and then get into the under-dash area and bring it all together. Sometimes, anyway...I tend to skip around a bit, but that's my loosely formulated Plan of Attack anyway! On this car, I decided to start with the tail lights. You'll be MILES ahead of the game if you have new tail light assemblies to start with, but 55 Chevys ain't all that popular I guess (!), so nobody sells whole assemblies for them...just lenses and trim bezels! That gives us a chance to spend a few hours refurbishing the ratty original housings and sockets enough to make do! (Did I mention that this was FUN as well as "easy"?!) The passenger side assembly came apart okay, and with a little deft effort, I was able to get the age-old bulb out and salvage the socket. I scraped and cleaned the contacts, then coated the base and bottom end of the new Sylvania Long Life 1157 bulb with a film of No-Ox-Id compound (more on this stuff in a minute) and locked it into place. I had removed the entire housing from the vehicle by cutting the crusty old wires going to the socket, leaving a short bit to connect the new wires to (they were fine up near the socket, the factory rubber coating and boot up there kept the wires in decent shape for about the first two inches out of the socket, which was all I needed). Something I insist on, is that each component have a dedicated ground wire going to it. Sure, the housings, sockets, etc tend to bolt or screw to the chassis and, in theory, should be grounded through the chassis...but one extra wire to each component isn't a big deal, and the payoff is that you virtually eliminate lots of potential 'gemlins' due to a poor or inconsistent ground...especially on older, rusty cars! This ensures that your bulbs will all light, and shine as bright as they should, without dimming, flickering or just plain not lighting because of a poor ground. Any component relying on it's mounting to the metal chassis for it's ground will still be grounded that way, but the added ground wire just makes your job that much more reliable. Think of it as if you are wiring a car with a fiberglass body...in such cases, you NEED to run a dedicated ground wire to each component in order to make it work. I wire my metal cars the same way! In this first photo, you can see the passenger side tail light housing ready to install back in the body. Note the ground wire screwed to the metal base down near the bottom of the housing, in the unused backup light area. (This car did not come with the optional reverse lights, and I wasn't adding them. You can see the factory plug over the light socket hole where the reverse light socket would go.) Also note how the harness has enough slack in it to allow the housing to come out this far. This only makes things easier for you in the future, should you need to do any service or trouble-shooting. (The bulb can be replaced by removing the lens only, the housing does not need to come out for bulb replacement in this particular case). (Don't ask about the driver's side housing...the socket was so rotted that it snapped and I had to modify a universal store-bought replacement to fit...like I said...FUN!!!!) Before the tail light housing was installed, though... I first tested it using the convenient battery under the hood of the car. Uising the existing couple inches of the original socket wires and a new length of ground wire screwed to the housing, I tried each of the two socket wires one at a time to determine which one was the bright (stoplight) wire and which was the dimmer (tail light) wire. This also showed me that the ground wire was good and that the bulb worked. I connected about a three foot length of orange 14ga wire to the stoplight wire, and the same length of pink wire to the tail light wire (long enough to go into the trunk area and route across to the driver's side where the wires would join the wires for the driver's side housing and splice into the 'rear light harness' which would run inside the car and up into the dash area). That done, I 'banded' the pink, orange and black wires together every few inches using small strips of electrical tape, then wrapped them completely in electrical tape for about two feet...to insure that I'd have a wrapped length long enough to feed from the housing, through the factory grommet inside the quarter panel and into the trunk area. The rest gets wrapped later, after it's routed and trimmed to length, leaving a couple inces of exposed wires to connect to the other side and the rear light harness before the junction area gets wrapped and tucked into place for good. Looking into the trunk area, you can see where my wrapped segment ended, showing loose colored wires. I see SO many cars 'wired' with loose wires like this strewn about that it boggles the mind...neatly wrapping your harnesses in tape (like the factories do it) makes your work a whole lot nicer, protects your wires better and keeps everything neat and out of the way. Plus, it really isn't difficult at ALL! No excuse not to do it, people! This photo shows you the rear light harness prior to installation. You can see the 'banding' every couple inches or so which holds the wires together prior to wrapping them neatly with the tape. When wrapping a harness, guesstimate the lenth you'll need, then stop short, leaving the last few inches loose to trim, fit, and wrap in the final installation (always guess to the LONG side when possible!). To wrap a banded harness, start at one end (usually the component end), and attatch the end of your tape to the harness at a slight angle, then...keeping it tight to the harness, work the roll of tape around the harness, overlapping each turn as you go until you reach the other end, or CLOSE to the other end. Once all connections are made, back up a few inches and start the wrapping process again to enclose the spliced area(s). A word here about wire gage, connectors and protectant. First up, I use at least 14 ga wire for everything, with larger wires used where a bigger load (more amperage) is expected. 16ga or even 18ga might be adequate for the lights and stuff...the factory wires sure were puny...but it doesn't hurt to go a wee bit bigger...as I like to employ a dose of 'overkill' when I wire a car! As far as crimp connectors go, I love 'em. If you use them correctly, and crimp them well with a decent crimping tool, you shouldn't have any worries. To insure it, though...I apply a dab of No-Ox-Id protectant to every connection, socket, and bulb in the vehicle. It's incredible stuff! It has the look and feel of ear wax, but just a light coat will prevent corrosion and keep those electrons flowing freely for years! As my dad taught me decades ago when he first introduced me to this stuff, "You don't have to use it on every connection...just the ones you want to work!" In many cases, there will be 'tabs' that held the stock wiring in place, such as was the case with my car. You can see how the completed rear light harness is tucked tightly into these existing tabs (minus one that I broke!), allowing my new harness to follow the original path into the interior where it was run along the door sill area and secured with nylon cable straps and small sheetmetal screws (the channel in this area was rotted, so I chose not to stick my new wires through it!). At this point, the rear light harness was tucked under the dash with enough extra wire on the ends to hook up to the required locations when I get to that point...and it ran from there back into the trunk and over to the passenger side light in a simple, easy and sanitary manner. Just about the way that GM did it, only with bigger wires, a ground wire and a fully wrapped harness. It's neat, clean and should provide years of trouble-free service! More to come as this project moves along...stay tuned!
Okay, let's move on to Day Two! This time, we'll go to the front of the car and see what awaits us there! The first order of business whenever you're about to mess with an existing electrical system, or start working on one from scratch, is to disconnect the battery cable. You can remove the Positive cable, the Negative cable, or both...but taking either one off will cut power to everything in the car, which is what you want! One nice thing about this project is that the engine compartment is pretty clean, making it easy to work in and see what you're doing. Trust me, you don't always have it this good when you embark on a total re-wire job!
Being that (for the moment) I'm still on the fence as to whether I want to retain the currently non-functional generator and regulator, or adapt an alternator to this car, I decided to shoot some pictures of the generator, regulator and horn relay for future reference, to see what wires went where after the old stock harness was removed from the engine bay.
Use Non-Adhesive harness tape instead of the electrical tape and you won't have a sticky mess to deal with at a later date... And... If you need to make a repair or change something down the road all you have to do is unwrap it and then re-wrap it. Al
Alright! Let's get into it again, shall we? (Remember, this is FUN!). At this point, I decided to get into the parking lights. I found that the socket was missing completely on one side, and badly corroded on the other. I removed the assembly with the bad socket from the car and the old socket literally crumbled with the slightest pressure, leaving the 'ring' in place on the old housing. Those rings are pretty soft, so a little effort with a screwdriver blade was all it took to remove it. I quickly 'dressed' the hole with a file and it was ready to accept a new socket. (Boy, we're making progress here! I love it!)
I took a break to dash off to the local parts store for a new socket, and found two of them in stock. I love it when things go this smoothly! Wow...the new socket assembly sure looked pretty! Nice brass terminal ends, a length of sheathing to protect the innards of the socket and everything! How spiffy! The tabs around the socket snapped nicely into the hole, but to insure that it stays put, I opted to use the retaining ring that came with the new socket. A dab of No-Ox-Id on the tabs helped the socket snap into place and would ensure a good 'double ground' to the light bucket, in addition to the dedicated ground wire I was installing.
And here it is! With a couple holes drilled and two screws holding the retaining ring in place (along with my ground wire), I had one parking lamp assembly ready to re-install!
Now, class...what do we do BEFORE re-installing any component or assembly? Anyone know? That's right! We TEST it, using that 12v battery conveniently located right in the vehicle we're working on! I mean, it's a brand new socket with a brand new bulb in it, so we know those sharp Taiwanese craftsmen won't let us down...but still, at the very least, we need to test each lead to determine which one is for the dim (parking light) side of the bulb, and which is for the bright (turn signal/flasher) side of the bulb. So, just as with the tail light assembly, we hold the ground wire to the negative post on the battery, and touch each of the other wires to the positive post individually to see which is the bright one and which is the dim one. Why do we do this? Read on! If you're using quality auto parts, the chances of instantaneous failure are greatly reduced, but in today's world, quality auto parts are getting harder and harder to come by. The local Murray's USED TO carry a brand called Cal-Trem (or something like that...Cal-Term maybe?) and I've had nothing but positive experiences with them. But, they recently switched over to Doorman electrical products, and I've had lots of problems with them, so I went to Advance Auto and bought these sockets in the form of a brand called Connect-Tite. You can imagine my glee when I tested the lamp only to see a quick spark followed by a puff of smoke! Upon further investigation, I disassembled the new socket after removing it from the housing found an exposed strand of wire touching the inner part of the socket, creating a dead short that arced enough to singe the socket and the base of the bulb...how cool! So, that's where today's segment ends! No parking lights until some GOOD old USED (or reproduction if available?) parking lamp assemblies with good sockets in them can be found and purchased! The whole experience underscores a VERY serious issue facing us car folk today...you can't build a quilty car without quality replacement parts...and quality replacement parts are quickly vanishing from the market, replaced with inferior goods from overseas! So, unless you stumble onto an old stash of NOS replacement parts, the quality of your builds is going to take a nose-dive, because the available parts just don't measure up anymore, and once-trusted brands are being taken off the shelf by parts chain bean-counters who see the cheaper, inferior products as a quick road to higher profits. But, this emphasizes why I stress the need to test the components before installing them. You can imagine the grief you'll encounter if you go ahead and install all these junk parts and THEN discover that they don't work, short out, catch on fire or whatever else! Better to know this ahead of time and only lose a LITTLE time and a few dollars, then to finish your project only to discover you've got to start all over again! More to come as the saga unfolds!
Great post. I'm gonna have to wire my car front to back from scratch. Where can you purchase that special grease at? Todd
Sure missed reading about the ol' Chevy with the 60 degree. You write in a fashion that even my boss could understand. (No, not her. She still wouldn't get it. ) Blue Jean will surely be a favorite H.A.M.B. opera for us to keep up on.
I'm getting ready to do the very same thing with my '56 Plymouth wagon - new wiring from front to back! I'm watching, because I sure as hell don't know everything!
My dad got that stuff YEARS ago when he worked in the garages at Detroit Edison, but it looks like it's still available... http://www.sanchem.com/aSpecialE.html
Next on my list as well! Great read, keep us updated! Care to quickly educate an electricalFNG on the joys of scratch wiring a push-button starter switch for a 289 SBF?
That's an easy one: A 289 uses a starter relay mounted somewhere on the inner fender (usually). It will have a battery cable run to it from the positive side of the battery, then another battery cable (called a switch-to-starter cable) will run from there to the starter motor. A much smaller wire will be connected to the "S" (for 'Start') terminal on the relay, and there MAY be a second (sometimes un-used) terminal marked "I" (for 'Ignition'). This was used in points type vehicles to provide full voltage to the coil while cranking. Anyway, just use the push-button to apply momentary current from the battery to the "S" terminal on the relay and the engine will crank over until the button is released. .
im saving this thread,,,i will be rewiring my car in the near future and this thread will definitely come in handy since im clueless when it comes to electrical stuff,,thanks for the post................
Today we'll attempt once more to complete the Front Light Harness for this car! I started early, so there should be PLENTY of time to sail right through this fairly simple task, right?! Okay, whenever you go to install new headlight wiring, and/or new headlights in an old car, you're never quite sure just WHAT you'll run into, so take a deep breath and prepare to dive in! Whew! Not so bad on the passenger's side! I start over here because I make the harness to run from this light over to the driver's side, then back along the inner fender panel to the firewall and ultimately into the interior. I found pretty much what I expected to see here...a crusty old section of the original headlight wiring and a rusty headlight bucket. The brass-plated wood screws or whatever holding the bezel on was a classy touch, but aside from that, nothing too out of the ordinary. The retaining ring was in decent shape at least, which isn't something you can often bet on!
When wiring a standard two-lamp car (one lamp per side), you can find a variety of connectors on the market with assorted colors on the wires, but the basic thing to remember is which prong does what on the back of the headlight bulb. You can use whatever color wire you wish, so long as you know what color wire is hooked to which prong position on the socket. The diagram below shows which prong is which, as seen when looking at the back side of your headlamp. The top one is for your low beams, the right one is for the high beams and the left one is your ground. I found some good quality headlight sockets at a local independent parts store and their color code made sense to me, so I kept the wires the same color throughout the harness. For my application, the ground wire is black, the low beams are white and the high beams have a red wire. I began making the harness by measuring out approximately enough wire to reach the other side of the car once being fed through the factory grommets and wiring clips (plus a couple of my own). I banded and taped the red, black and white wires together and wrapped them from the headlight socket back about far enough so that I'd be sure the wrapped part of my new harness would reach through the fender and the grommet by the radiator core support. Right near there is the screw where the headlamps were grounded by Chevrolet back in 1955, so my ground wire went to that screw as well, but of course I added to that. (More on that in a minute). Now, just because I don't have good parking light housings (or sockets) for this car at the moment doesn't mean we can't include the parking light wiring in this harness. It's a lot easier to do it now and just leave the ends taped off and tucked inside the empty socket holes in the parking light housings then it would be to go back and make another harness to 'piggyback' the headlight wiring. This is why I stated from the start that you should have a general 'plan' in mind as to what accessories and components you want your car to have, so that you can include them all in your new wiring harness, even if they won't be hooked up until later on. As always, I used a dedicated ground wire in the parking lamp wiring, along with a yellow wire to power the parking light bulb. This two-wire harness was banded, wrapped and routed into place, then the ground wire for the parking lamp and the ground wire for the headlamp were joined in a single ringlet terminal to be installed where the factory ground location was on the core support. I removed the 'ground screw' and took it into the garage to clean it and the lock washer on the wire wheel. Once clean, I coated the washer and screw with a light film of No-Ox-Id and made another black wire with a ringlet to join the ground wires for the lights on that same screw. Both ringlets got a dab of protectant and were fastened into place. That ground wire will run inside the car to a 'ground terminal' that will be added later. This way, the lights are grounded to the chassis in the factory location, but will have the additional 'help' of a dedicated ground wire to insure reliable operation for many years. The photo shows the semi-complete passenger's side light harness ready to be wrapped and routed over to the driver's side.
Here's the passenger's side all done and tucked into position. You can see the ground wires attached to the screw and the fully taped harness routed through the factory grommets and clips as they should be. It looks a lot nicer than a jumble of colored wires run loosely along the same route!
Well, things were going along pretty good, so I was optimistic that I'd have this job wrapped up in no time! So, with that mindset, I went to remove the air cleaner so I could get my cordless drill in position to pop a couple holes for the nylon cable clamps I installed to keep the harness for the passenger's side out of the fan. Hmmm...the air cleaner was kinda wobbly...I wonder why that might be??? The problem was quickly obvious...the rocket-scientist previous owner had somehow managed to snap the 'bridge' off the carb (where the air cleaner stud goes) and just sort of...you know...left it like that! (Although he did thread a sheet metal screw through the carb to I guess catch the broken part in some imaginary way???). FUCKING AWESOME!!! Add one more thing to the list of repairs! I have an idea of how I'll install a new air cleaner, but that'll come later...in another tech thread!
Okay, with the passenger's side harness in place, I was ready to breeze right through the driver's side. I removed the classy brass drywall screws or whatever they were holding the bezel in place, and discovered a fantastic feat of engineering on the previous owner's part! Dig the way he just duct-taped the headlamp to the back of the bezel like that!! How fucking cool is THAT?! Why waste time messing with those pesky retaining rings and screws, when you can just TAPE that bulb in place! RIGHT ON!!!! Well, time to close up the garage and head off to the parts store for a retaining ring!
Once I returned with a new retaining ring, I was able to repeat the same basic procedure from the other side and got the driver's side harness made up and routed. I employed the factory 'ground screw' on this side as well, and popped open the box with the new headlight in it (I never trust existing bulbs...who knows how old they are or if they're good? I had picked up new bulbs a couple days ago). I found my new headlamp cracked, so I dashed off to the parts store once again to exchange it! Returning home, I installed the driver's side headlight WITH that snazzy new retaining ring and was ready to continue!
The wiring for both headlights (as well as the parking lights) was fed through the grommet on the driver's side, and the like-colored wires were spliced together and ready to hook up to single wires running into the passenger compartment through the firewall.
Now, with the Front Light Harness complete and tucked neatly into place, we have a simple, sanitary and reliable harness that will be connected to the proper sources inside the car when that segment arrives! At this point, the vehicle's lights (front and rear) are all wired and run back to the under-dash area for final hook up. That part is pretty easy, as you'll see later...and isn't normally as time-consuming as the harness installation is. We'll still need to address the engine wiring and charging system before we can complete our total re-wire, so stay tuned for that fun and exciting chapter...coming soon to a HAMB near you!
Okay, we got more parts...and it isn't raining or cold today, so work can continue! I decided to axe the generator and regulator in favor of a more modern (1970s era) internally regulated GM alternator, so I needed to find a bracket to mount one to the old 235 Stovebolt engine. Luckily, Tman suggested placing an inquiry to Alan Grove Components and I was able to order one for this exact application (1955-62 235 and 261 engines) for $60 shipped. That left me with some down time to get that old boat-anchor generator off the car! (Now you're starting to see why it can take a while to complete a re-wiring job...you often have to stop and replace, restore, fix, upgrade or modify components, sockets and such along the way. But, in the end, you'll have a dead-nuts reliable electricl system, so the time spent NOW will save you much grief later on!) Removing the generator is a simple task, but be forewarned...they ain't light!!
The Jalopy Journal
